Circuit and method for preventing erroneous opening and closing in an automatically/manually foldable portable radio phone

Abstract

Disclosed is a circuit and method for preventing erroneous opening and closing caused particularly, by use of a DC motor in an automatically/manually foldable portable radio terminal having a main body and a sub-body rotatable with respect to the main body. In the circuit, a motor provides rotating force to automatically raise or lower the sub-body, a motor driver drives the motor according to a motor driving direction control signal, an inverse electromotive force eliminator eliminates inverse electromotive force by opening or shorting both terminals of the motor according to an automatic mode or a manual mode, and a motor power controller controls supplying a driving power voltage to the motor. In the method of operating a folder, it is determined whether an automatic folder operation key has been pressed. Upon receipt of the automatic folder operation key input, a rectifier is turned on to open both terminals of a motor. At the end of the opening of the motor terminals, the motor is driven.

What is claimed is:  
     
       1. A circuit for preventing erroneous opening and closing in an automatically/manually foldable portable radio terminal having a main body and a sub-body rotatable with respect to the main body, comprising: 
       a motor for providing a rotating force to automatically raise or lower the sub-body;  
       a motor driver for driving the motor according to a motor driving direction control signal;  
       an inverse electromotive force eliminator for eliminating an inverse electromotive force by opening or shorting both terminals of the motor according to an automatic mode or a manual mode; and  
       a motor power controller for controlling supplying a driving power voltage to the motor.  
     
     
       2. The circuit of  claim 1 , wherein the inverse electromotive force eliminator shorts the terminals of the motor in the manual mode. 
     
     
       3. The circuit of  claim 1 , wherein the inverse electromotive force eliminator opens the terminals of the motor in the automatic mode. 
     
     
       4. The circuit of  claim 1 , wherein the inverse electromotive force eliminator includes a photo MOS relay. 
     
     
       5. The circuit of  claim 1 , wherein the motor power controller includes a battery for providing a predetermined power voltage, and a rectifier for rectifying the power voltage received from the battery and feeding the rectified voltage to the motor driver and the inverse electromotive force eliminator. 
     
     
       6. The circuit of  claim 1 , wherein the inverse electromotive force eliminator includes transistors at both the terminals of the motor, the transistors turning on, connecting to ground terminals, and shorting the terminals of the motor in the manual mode and turning off and opening the terminals of the motor in the automatic mode. 
     
     
       7. A method of operating a folder in an automatic mode in an automatically/manually foldable portable radio terminal, comprising the steps of: 
       determining whether an automatic folder operation key has been pressed;  
       turning on a rectifier to open both terminals of a motor upon receipt of the automatic folder operation key input; and  
       driving the motor at the end of the opening of the motor terminals.